WATER SUPPLY OF TOWNS. 
18 7 
which he considered as the workmanship of land-snails. 
He considered that by means of the acid with which they 
were provided snails could make perforations into the most 
solid forms of limestone, but the perforations were unlike 
those made by any other animals, or those made by the 
salt of the sea and the carbonic acid of the atmosphere. 
These perforations were never found where the rain and 
frosts could operate, and always had the aperture down¬ 
wards. From observations made at Richborough last year, 
he had concluded that these perforations were not made 
to a greater depth than an inch in a thousand years.” 
Subsequently he seems to have leaned to the opinion 
that the perforations were bored by the rasp-like tongues 
of the snails. It was with a view to the establishment or 
disproof of this theory that his wife and her youngest 
daughter Caroline during his illness at Islip made a large 
collection of the tongues of both land and fresh-water 
snails, which they mounted in Canada balsam, and careful 
drawings were made of them. 
Another favourite topic of discussion at the Society of 
Civil Engineers was the water supply of large towns. 
The following extract from the Bridgewater Treatise on 
artesian wells shows the practical value Professor Buck- 
land attributed to this “ prime necessary of life,” as well as 
the poetic view with which he regarded it :— 
“ In some places application has been made to economical 
purposes, of the higher temperature of the water rising from 
great depths. In Wurtcmberg, Von Bruckmann has 
applied the warm water of artesian wells to heat a paper 
manufactory at Heilbronn, and to prevent the freezing of 
common water around his mill wheels. The same practice 
is also adopted in Alsace, and at Canstadt, near Stuttgard. 
It has even been proposed to apply the heat of ascending 
